1. Field of the Invention
The present invention relates to a plasma display panel device and more particularly to a plasma display panel device having a pair of row electrodes made up of a scanning electrode and a common electrode (sustaining electrode) which provide one display row formed in parallel with a plane of a front substrate (scanning substrate) facing a rear substrate.
The present application claims priority of Japanese Patent Application No. JP2001-230602 filed on Jul. 30, 2001, which is hereby incorporated by reference.
2. Description of the Related Art
A Plasma Display Panel device ((hereinafter, may be referred simply to as a PDP device) is classified into one of three types; one being an AC (Alternating Current)-type PDP device conventionally using an AC as a driving power source, another being a DC (Direct Current)-type PDP device using a DC as the driving power source, and a third being a hybrid-type PDP device using the AC and DC in combination. Of them, the AC-type PDP device is widely used since it is of a comparatively simple structure and its screen can be easily made large.
Of the AC-type PDP device, a PDP device of a three-electrode surface discharge type, in particular, has a configuration in which a pair of row electrodes made up of a scanning electrode and a common electrode which provides one display row (line) is formed in parallel with a plane of a front substrate facing a rear substrate and a column electrode (address electrode) is formed on a rear substrate so as to be orthogonal to a pair of row electrodes and, by driving the address electrode (data electrode) and the scanning electrode using a driving voltage, writing discharge is performed to select a unit cell (hereinafter being referred to as a display cell) to be turned ON (to be displayed) and then sustaining discharge is performed by surface discharge of a display cell selected by driving the scanning electrode and the common electrode using a driving voltage. In the above PDP device, since no ion bombardment causing deterioration occurs between an ion of high energy being produced on the front substrate at a time of surface discharge and a phosphor formed on the rear substrate, which enables a life to be made longer. As a result, the PDP device is widely employed.
FIG. 8 is a schematic plan view showing configurations of main components of a conventional AC-type PDP of a three-electrode surface discharging type. In the conventional AC-type PDP, as shown in FIG. 8, each of scanning electrodes 51 and each of common electrodes 52 making up a pair of row electrodes that provides one display row are formed in parallel with a row direction H on a screen, with a surface discharge gap (not shown) being put between the scanning electrode 51 and common electrode 52, on a face of a front substrate (not shown) made up of a transparent substrate that faces a rear substrate (not shown). The scanning electrode 51 includes a transparent electrode 51A and a bus electrode 51B (trace electrode) formed on a part of the transparent electrode 51A, having a resistance being lower than that of the transparent electrode 51A so as to lower a line resistance. The common electrode 52 includes a transparent electrode 52A and a bus electrode 52B (trace electrode) formed on a part of the transparent electrode 52A, having a resistance being lower than that of the transparent electrode 52A so as to lower a line resistance.
On the other hand, address electrodes 54 making up column electrodes are formed, in parallel with a column direction V on a screen, on a face (being opposite to the front substrate) of a rear substrate (not shown) made up of a transparent substrate that faces the front substrate and each of the address electrodes 54 is arranged in such a manner as to be put between ribs (partition walls) 55 each being formed in parallel with the column direction V. A display cell is partitioned by each of ribs 55 to be a plurality of display cells 56. The Plasma display panel (hereinafter, may be referred to as a PDP panel) is so constructed that the front substrate and the rear substrate are integrally assembled with space for discharging gas being put between them and, by connecting a driving circuit to the PDP panel, the AC-type PDP device is fabricated. In following descriptions, to get an easy understanding, the PDP panel alone is described simply as the AC-type PDP device.
In the AC-type PDP device having configurations described above, an arbitrary image is displayed on a screen by performing writing discharge (during an addressing period) to select a display cell 56 to be turned ON (to be displayed) out of a plurality of display cells 56 through an application of a driving voltage (high-frequency pulse) to drive the address electrode 54 and scanning electrode 51 and by performing sustaining discharge using a surface discharge method of a display cell 56 selected through an application of a driving voltage to drive the scanning electrode 51 and the common electrode 52.
FIG. 9 is a schematic plan view showing configurations of main components of the conventional AC-type PDP device. FIG. 10 is a cross-sectional view showing a method for driving the conventional AC-type PDP device. In the conventional AC-type PDP device, as shown in FIG. 9, a pair of the scanning electrode 51 and the common electrode 52 that provide one display row is formed on a display cell 59 in parallel with a line direction H in a front substrate (not shown). Each of driving terminals S1, S2, S3, . . . Sn is formed at one end (at an end on the right side in the example) of each of the scanning electrodes 51 and each of driving terminals C1, C2, C3, . . . Cn is formed at another end (at an end on the left side in the example) of each of the common electrode 52. A bus electrode 60 is connected to each of the driving terminals C1 to Cn. Moreover, as described above, the rear substrate is arranged in such a manner so as to face the front substrate in a column direction V and column electrodes (address electrodes) are formed on a face which faces the rear substrate in such a manner as to be orthogonal to the pair of the row electrodes being made up of the scanning electrode 51 and the common electrode 52.
In the configuration of the conventional AC-type PDP device shown in FIG. 9, an image is displayed, after a display cell 59 has been selected during an addressing period, by applying a high-frequency pulse of several 100 KHz to the scanning electrode 51 and the common electrode 52 for the display cell 59 selected during a sustaining discharge period to perform sustaining discharge.
Here, as shown in FIG. 9, in the conventional AC-type PDP device, the driving terminals S1 to Sn of the scanning electrode 51 are formed at an end on a right side of a PDP panel in FIG. 9 and driving terminals C1 to Cn of the common electrode 52 are formed at an end on a left side of the PDP panel in FIG. 9, each of which is positioned in a different place. Therefore, when the sustaining discharge is performed, as shown in FIG. 10, a current always flows in a same direction by the sustaining discharge through both the scanning electrode 51 and the common electrode 52 at a time when the scanning electrode 51 is driven by a first driving circuit 61 and at a time when the common electrode 52 is driven by a second driving circuit 62. As a result, a current loop 65 is formed which connects the first driving circuit 61, a GND plate 63, the second driving circuit 62, and a PDP panel 64. A loop antenna is formed by the current loop 65. Then, from this loop antenna, strong electromagnetic radiation occurs which has a frequency component in a wide band.
Since such the electromagnetic radiation has an adverse effect on electromagnetic environments in electronic devices, electric appliances, or a like in general homes, to reduce the electromagnetic radiation, it is necessary that an electromagnetic shield is provided on a PDP device. However, since a thin configuration of a PDP device is its prime selling point, such the electromagnetic shield not only hinders the thin configuration but also causes an increase in costs.
A PDP device configured so as to reduce electromagnetic radiation is disclosed in Japanese Patent Application Laid-open No. JP2000-89723 (hereinafter referred to as a first conventional technology). In the above PDP device, as shown in FIG. 11, both a scanning electrode 101 and a common electrode 102 for a first display row are drawn out from a drawing-out position on a left side 109 and both the scanning electrode 110 and the common electrode 111 for a second display are drawn out from a drawing-out position on a right side 118 and, hereinafter, the drawing-out positions of the scanning electrode and the common electrode are alternately arranged in this order for every display row. Reference numbers 119 to 121, 122 to 124, . . . show the address electrodes (for a red color, green color, and blue color). By configuring as above, since the scanning electrode 101 (110, . . . ) and common electrode 102 (111, . . . ) for each of the display rows can be drawn out in a same direction and a current produced through sustaining discharge always flows in a different direction through the scanning electrode 101 (110, . . . ) and common electrode 102 (111, . . . ), magnetic flux occurring in every unit of the display row is erased and electromagnetic radiation can be reduced.
Similarly, a PDP device is disclosed, for example, in Japanese Patent Application Laid-open No. JP2000-294152 (second conventional technology) in which magnetic flux occurring in every two display units is erased. In the disclosed conventional PDP, as shown in FIG. 12, same scanning electrodes (SCN1) for the first and second display rows and same common electrode (SUS1) are drawn out from a position on a left side and are connected to the scanning electrode driving circuit 200 and the sustaining electrode (common electrode) driving circuit 300, respectively. Since similar configurations for the display row below are provided, the scanning electrodes 101 (110, . . . ) and common electrodes 102 (111, . . . ) for all other display rows can be drawn out from a same direction. Moreover, reference numbers D1, D2, . . . show address electrodes to be connected to a data (address) electrode driving circuit 400.
Each of the conventional PDP devices described as the first and second technologies can reduce electromagnetic radiation, however, each of them has a problem.
First, in the first conventional technology, each of a plurality of display cells in which the scanning electrode 101 and the common electrode 102 are formed has a different impedance in every display cell due to a difference in the drawing-out position 109 on the left side of the panel caused by a positional variation in a row direction H. Therefore, since light-emitting luminance and/or controlled state are made different in every display cell, a uniform state of light emission for displaying cannot be achieved.
Next, in the second conventional technology, since magnetic flux occurring in alternating sequence of display rows is erased and potentials of the two scanning electrodes for the two display rows and of the two common electrodes for the two display rows become same, individual selection of the scanning electrode or common electrode is made impossible. Therefore, since same scanning electrodes or same electrodes can always display same contents only, high-definition display of an image becomes difficult. To solve this problem, a method may be available in which address electrodes are separated depending on either of an odd row or an even row, however, to achieve this, a very complicated driving circuit is required, which inescapably causes very high manufacturing costs.